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<div dir="ltr"><span style="font-size: 12pt;">We've been looking at compiler queue load, both under dynamic and static configurations and added jdk.CompilerQueueUtilization to the JFR logging to help with this.</span></div>
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<div>There's much discussion in JBS ([1], [2] and [3] amongst others) and on the mailinglists regarding 1 vs 2 queues, shared threads vs dedicated and the benefits/tradeoffs of dynamic compiler threads.</div>
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<div>Our proposal is to allow the 1:2 ratio (c1:c2) to be overridden on the command line with a goal to allow experimentation that might help either solidify the rational around the current settings or set us on a new path to make some changes. Further it
could allow developers to fine tune the ratio for their workload specific needs.</div>
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<div>Something like -XX:CICompilerThreadRatio="2:3" (default is "1:2" which matches the current settings)</div>
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<div>Note that the math to calculate the allocation of CICompilerCounts to C1 and C2 would remain integer, ensuring that the default ratio of 1:2 allocates the same number of threads to C1 and C2 as it does today.<br>
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<div>Other than adding a new command line option, the only change would be in the initialize method in src/hotspot/share/compiler/compilationPolicy.cpp</div>
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<div><span style="font-size: 12pt;">There's also a thought on setting the compiler threads explicitly that we're happy to table until later: -XX:CICompilerThreadCounts="3:4"; in this case we'd compute CICompilerCounts as the sum of C1 and C2 threads.</span></div>
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<div><span style="font-size: 12pt;">Thoughts and questions appreciated, thanks in advance</span></div>
<div>Mat</div>
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<div>[1] https://bugs.openjdk.org/browse/JDK-8134507</div>
<div>[2] https://bugs.openjdk.org/browse/JDK-8198756</div>
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<div dir="ltr"><span style="font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; line-height: normal; font-weight: 400;">[3] </span><span style="font-family: Aptos, Arial, Helvetica, sans-serif; font-size: 12pt; line-height: normal; font-weight: 400;">https://bugs.openjdk.org/browse/JDK-8302264</span><br>
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